There are numerous Gram positive bacteria which have been of interest in the fields of medicine and epidemiology because of their potential to cause a myriad of infectious diseases in humans and animals. One such Gram positive bacterium, Enterococcus faecalis, belongs to the commensal flora in mammalian intestines. It has also long been known as a major causative agent of bacterial endocarditis (Murray, 1990). During the last decades, E. faecalis has increasingly emerged as an opportunistic nosocomial pathogen, typically causing infections in hospitalized patients receiving antibiotic therapy. Clinical strains of this bacterium frequently harbor a multitude of acquired and intrinsically evolved resistance mechanisms toward the most commonly used antibiotics, which has complicated the treatment of enterococcal infections (Murray, 1990, 1999) (Tailor, 1993) (Huycke, 1998). Many of the antibiotic resistance genes are located in mobile genetic elements, e.g., small plasmids and transposons (Paulsen, 2003) This has raised fears for genetic transfer of resistance determinants from this organism to other bacterial species, e.g., the recently documented transfer of vancomycin resistance to Staphylococcus aureus (CDC, 2002). Still other Gram positive bacteria are known which commonly cause infections which are hard to control, including other bacteria from the Enterococcus genus, including Enterococcus faecium, as well as bacteria from species Streptococcus, such as Streptococcus mutans and pneumoniae, Staphylococcus, such as Staphylococcus aureus and epidermidis, and Bacillus, such as Bacillus anthracis. 
The ability to adhere to mammalian tissue is a critical step in the colonization and onset of microbial infections. However, in light of the many unknown factors regarding microbial adherence, it remains a challenge to study and utilize information obtained regarding relatively little known adhesion mechanisms of Gram positive bacteria so as to provide a means for developing alternative antibacterial therapies. One such inroad into developing such therapies is the presence of the human extracellular matrix underneath epithelial and endothelial cells which is a complex, dynamic and multifunctional structure consisting mainly of collagens and other glycoproteins. As one of the outermost layers to external environment, it is a major adhesion target and entry point for pathogenic bacteria (Foster and Hook, 1998) (Westerlund and Korhonen, 1993). Numerous bacterial adhesins that specifically bind to ECM components have been characterized at the molecular level. A group of related cell surface proteins from Gram-positive bacteria, collectively designated MSCRAMM® proteins (microbial surface components recognizing adhesive matrix molecules) bind to major components of the ECM, such as collagens, fibronectin, laminin, fibrinogen, keratin, vitronectin and bone sialoprotein (Patti, 1994) (Foster and Hook, 1998) (Tung, 2000) (O'Brien, 2002). MSCRAMM® proteins are mosaic proteins that typically consist of an N-terminal signal sequence for Sec-dependent transport across the cytoplasmic membrane, followed by an N-terminal A domain which exhibits the binding activity in most cases and repetitive B domains that confer fibronectin binding in a group of fibronectin binding MSCRAMM® protein (Joh et al., 1994). Covalent attachment to the bacterial cell wall is mediated through a C-terminally located LPxTG motif preceded by a cell wall spanning domain and followed by a hydrophobic trans-membrane region and, finally, a cytosolic tail composed of a short sequence of positively charged amino acid residues (Schneewind et al., 1995) (Mazmanian et al., 2001).
In any event, it remains a distinct problem in the field of infectious diseases to develop new means of countering a wide range of bacterial infections in an efficient and effective manner without the potential of increasing the development of antibiotic-resistant bacterial strains. Moreover, in light of the potential problems caused by bacterial strains and antibiotic-resistant strains in general, particularly in hospitalized patients, it is increasingly important to develop methods to counteract such infections without utilizing antibiotics or increasing the likelihood that antibiotic-resistant strains will develop. It is thus highly desirable to develop new means for identifying, treating and preventing infectious diseases caused by Gram positive bacteria, and to develop means for identifying and isolating new MSCRAMM® proteins from such bacteria which will allow the generation of antibodies thereto which will lead to new methods for treating and preventing the spread of infections from Gram-positive bacteria.